# Math Help - Decay Rate

1. ## Decay Rate

Implants of iodine-125 with a half-life of 60.1 days are used to treat prostate cancer. The implants are left in the patient and never removed. The amount of energy from the implant tht ais transmitted to the body is measured in rem units and is given by the integral from 0 to a of Poe^-ktdt where k is the decay constant for the radioactive material, a is the number of years since the implant, and Po is the initial rate that energy is being transmitted.

a. Find the decay rate k of iodine-125
b. How much energy(measured in rems) is given off the first month if the initial energy rate is 10 rem per yr?
c. What is the total amount of energy that the implant will give off over all time?

2. In General

k = ln(2)/halflife

k = ln(2)/60.1